For #3, I vaguely recall Steve mentioning in some post somewhere that NPR’s don’t quite research tech the way we do. While we have granular control in researching individual technologies, the NPR’s research large bulk lots of technology at once.
In other words, we can get individual new techs relatively quickly, while it can take an NPR some time to research anything new at all....but when it does it’s a large package of technologies all at once.
I suspect that with advanced enough tech, and a slow enough research modifier, you might indeed see a century or so before the NPR unlocks it’s next large tech package. That would mean it just keeps building more and more of the exact same ships until then.
Edit: Took some digging, but found the post from a couple months back. Ironically in reply to a bug report about NPR’s seemingly not researching new tech in a quarter speed research game.
The NPRs don't do research projects in the same way as players. Instead, they research groups of projects linked to their design theme. The cost and results of the research is the same and they still use the output from research facilities to generate research points, but it is handled in the background rather than via the UI, which means you won't see any NPR research in the DB. It also takes a while to research a project group, after which they get all the new techs at the same time.